Polyhydramnios, transient antenatal Bartter's syndrome, and MAGED2 mutations

Item Type:	Article
Title:	Polyhydramnios, transient antenatal Bartter's syndrome, and MAGED2 mutations
Creators Name:	Laghmani, K. and Beck, B.B. and Yang, S.S. and Seaayfan, E. and Wenzel, A. and Reusch, B. and Vitzthum, H. and Priem, D. and Demaretz, S. and Bergmann, K. and Duin, L.K. and Göbel, H. and Mache, C. and Thiele, H. and Bartram, M.P. and Dombret, C. and Altmüller, J. and Nürnberg, P. and Benzing, T. and Levtchenko, E. and Seyberth, H.W. and Klaus, G. and Yigit, G. and Lin, S.H. and Timmer, A. and de Koning, T.J. and Scherjon, S.A. and Schlingmann, K.P. and Bertrand, M.J.M. and Rinschen, M.M. and de Backer, O. and Konrad, M. and Kömhoff, M.
Abstract:	BACKGROUND: Three’ pregnancies with male offspring in one family were complicated by severe polyhydramnios and prematurity. One fetus died; the other two had transient massive salt-wasting and polyuria reminiscent of antenatal Bartter’s syndrome. METHODS: To uncover the molecular cause of this possibly X-linked disease, we performed wholeexome sequencing of DNA from two members of the index family and targeted gene analysis of other members of this family and of six additional families with affected male fetuses. We also evaluated a series of women with idiopathic polyhydramnios who were pregnant with male fetuses. We performed immunohistochemical analysis, knockdown and overexpression experiments, and protein–protein interaction studies. RESULTS: We identified a mutation in MAGED2 in each of the 13 infants in our analysis who had transient antenatal Bartter’s syndrome. MAGED2 encodes melanoma-associated antigen D2 (MAGE-D2) and maps to the X chromosome. We also identified two different MAGED2 mutations in two families with idiopathic polyhydramnios. Four patients died perinatally, and 11 survived. The initial presentation was more severe than in known types of antenatal Bartter’s syndrome, as reflected by an earlier onset of polyhydramnios and labor. All symptoms disappeared spontaneously during follow-up in the infants who survived. We showed that MAGE-D2 affects the expression and function of the sodium chloride cotransporters NKCC2 and NCC (key components of salt reabsorption in the distal renal tubule), possibly through adenylate cyclase and cyclic AMP signaling and a cytoplasmic heat-shock protein. CONCLUSIONS: We found that MAGED2 mutations caused X-linked polyhydramnios with prematurity and a severe but transient form of antenatal Bartter’s syndrome. MAGE-D2 is essential for fetal renal salt reabsorption, amniotic fluid homeostasis, and the maintenance of pregnancy. (Funded by the University of Groningen and others.)
Keywords:	Bartter Syndrome, DNA Sequence Analysis, Fetal Death, Fetal Diseases, Fetus, Kidney, Member 1 Solute Carrier Family 12, Mutation, Neoplasm Antigens, Pedigree, Polyhydramnios, Pregnancy, Premature Birth, Signal Transducing Adaptor Proteins, Sodium Chloride Symporters, X-Linked Genetic Diseases
Source:	New England Journal of Medicine
ISSN:	0028-4793
Publisher:	Massachusetts Medical Society
Volume:	374
Number:	19
Page Range:	1853-1863
Date:	12 May 2016
Official Publication:	https://doi.org/10.1056/NEJMoa1507629
PubMed:	View item in PubMed

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